Disposable lighters generally comprise, as noted above, a container for a gasifiable liquid fuel, namely, a hydrocarbon such as butane or mixtures of butane with other hydrocarbons, a valve arrangement at an upper portion of this vessel which can form a nozzle or outlet for a stream of the gasified fuel when the valve is opened, e.g. by manipulation of a lever, and a striking mechanism for generating a spark to ignite this stream of fuel.
A unique flow control system for disposable gas lighters of this type is disclosed in U.S. Pat. Nos. 4,101,262 issued July 18, 1978 and 4,224,020, issued Sept. 23, 1980, and comprises a filter disposed between the valve and the fuel supply, the filter comprising a porous membrane wettable by the hydrocarbon fuel and having porosity characteristics determined at the time of manufacture and establishing the height of the flame.
The advantage of the use of this membrane, which spans the space between the reservoir and the release valve, is that special means for adjusting flame height can be eliminated and/or an excessive flame height can be prevented, thereby restricting the possibility of danger to the user if the flame height has been improperly set by any adjustment mechanism.
Thus the result is a reducing valve system which makes it possible to obtain a constant gas outflow and therefore a constant flame height which is practically independent of the age of the lighter and the ambient temperature.
This arrangement and arrangements which allow adjustability of the flame height are frequently provided with wicking structures leading from the fuel reservoir to the valve system. The wicking structure is designed to draw the liquid fuel into an evaporation chamber in which thermal energy generated by ambient temperature or the flame and transmitted to the evaporation chamber ensures evaporation of the liquid fuel in a uniform manner.
Systems have been developed, e.g. as described in U.S. Pat. No. 4,060,202, granted Nov. 29, 1977, to promote the transfer of heat into the region at which evaporation is to occur.
Another advantage of the provision of means for establishing a fixed flame height in the manner described is that the means for controlling the flame height can be eliminated and the cost of the unit reduced, while avoiding any danger which may result from a malfunction of this control means.